The invention relates to an arrangement for the prestrengthening of at least two thread components that are to be twisted together. The arrangement includes a drawing device for the thread components that are aligned in parallel to one another, false-twist elements that are connected behind the drawing device, guide elements for the guiding together of the thread components behind the false-twist elements, a device for the withdrawing of the thread components and a device for the winding of the guided-together thread components on a spool serving as a feed spool for a twisting arrangement.
In other arrangements of this type (EP-A Nos. 38 143, 70 210, 126 659), the thread components are drawn to the desired yarn size in drawing means. Subsequently, they pass through false-twist elements in which they are strengthened, without receiving a true twist, to such an extent that they can be wound up perfectly and can pass through a subsequent twisting process. By the false-twisting, the thread components are only slightly prestrengthened, without receiving a twist, so that during the subsequent twisting, no twist has to be undone in the thread components. This will result in significantly higher production speeds at reduced costs. By the guiding-together of the thread components and the joint winding-up, the advantage is achieved that the absolute firmness of the two thread components is practically doubled, so that sufficient firmness exists for the subsequent twisting process, although the individual thread component has a relatively low firmness. In known arrangements, unless the fiber components pass jointly through the same false-twisting element, the guiding-together of the fiber components takes place behind the false-twist elements. In that case, a deflection must take place in order to bridge the distance at which the fiber components are supplied out of the pertaining drawing means. These deflections behind the false-twist elements result in an increased stress to the thread component so that, particularly at these points, there is the danger of a breakage of the thread component.
An object of the invention is to construct an arrangement of the initially mentioned type in such a way that the guiding-together a converging toward one another of the thread components behind the false-twist elements is connected with a strain that is as low as possible so that the danger of a breakage of the thread components is reduced.
This object is achieved by arranging the false-twist elements in an inclined position with respect to the transport direction of the drawing device such that the thread components converge toward one another so that at least a part of the deflection required for the guiding-together on converging of the thread components toward one another takes place between the drawing device and the false-twist elements.
By this arrangement, the deflection of the thread components is displaced to a larger part into the area between the drawing device and the false-twist elements so that the angle of deflection behind the false-twist elements can be correspondingly smaller. In this case, the false-twist elements provide the thread components with a false twist that is effective upstream and that acts as a protective twist for the thread components approaching the false-twist elements. Therefore, the thread components in this area have a relatively high firmness and are not so endangered by a deflective guiding as in the area behind the false twist elements in which the false twist has already become undone, and the only prestrengthening is caused by shiftings of fibers without any twist in the thread components.
According to other advantageous features of certain preferred embodiments of the invention, it is provided that, in each case, at least one guiding element is arranged between the drawing device and the false-twist elements. These guiding elements ensure that the moving direction of the thread components in the drawing device is not disturbed. In a further advantageous development, it is provided that the guiding elements, in each case, are arranged at a distance from the pertaining drawing device that is shorter than the staple length of the fiber material of the thread components. The guiding elements, at which the deflection takes place, act as a twist brake so that the false twist is stopped essentially in the area of the guiding elements. Nevertheless, because of the stability of the fiber component chosen, sufficient stability of the thread is maintained.
According to other advantages features of certain preferred embodiments of the invention, it is provided that the guiding elements that are connected in front of the false-twist elements are aligned with respect to the false-twist elements in such a way that a straight course of the thread component exists through the false-twist elements. As a result, it is ensured that the providing of the false-twist is not hindered. For the same purpose, it is provided in a further development that the guiding elements connected behind the false-twist elements are aligned with respect to the false-twist elements in such a way that a straight course of the thread components is obtained through the thread elements.
According to other advantageous features of certain preferred embodiments of the invention, it is provided that air nozzles are provided as false-twist elements. These types of air nozzles can more easily be arranged at a slope than mechanical elements because the inclining of the mechanical false-twist elements requires a more complicated drive that is advantageously derived from a continuous driving element that drives all operating points of one machine.
According to other advantageous features of certain preferred embodiments of the invention, it is provided that each false-twist element contains two air nozzles that are connected behind one another. This development is particularly suitable for relatively wide thread components. However, it should be taken into account in this case that the air nozzles do not have the effect that is known from the air spinning process; i.e., no individual threads are to be formed that have a relatively high inherent stability that are suitable, for example, for a weaving process. The prestrengthening, in the case of a largely unchanged parallel alignment of the fibers, must only be so high that an intermediate winding for the subsequent twisting process is possible.
According to other advantageous features of certain preferred embodiments of the invention, it is provided that the false-twist elements are arranged on a joint holding part. In an advantageous further development, it is also provided in this case that the guiding elements that are connected in front of and/or behind the false-twist elements are arranged on the joint holding part of the false-twist elements. As a result, a constructionally simple structural unit is obtained that, if necessary, can be exchanged for servicing or for an adapting to other fiber materials.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.